US4039753A - Singing suppressor device - Google Patents

Singing suppressor device Download PDF

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Publication number
US4039753A
US4039753A US05/573,989 US57398975A US4039753A US 4039753 A US4039753 A US 4039753A US 57398975 A US57398975 A US 57398975A US 4039753 A US4039753 A US 4039753A
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United States
Prior art keywords
frequency
audio
singing
signal
generator
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Expired - Lifetime
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US05/573,989
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English (en)
Inventor
Geza Balogh
Emil Sesztak
Karoly Szabados
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Elektroakusztikai Gyar
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Elektroakusztikai Gyar
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    • G—PHYSICS
    • G10—MUSICAL INSTRUMENTS; ACOUSTICS
    • G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
    • G10K11/00—Methods or devices for transmitting, conducting or directing sound in general; Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
    • G10K11/002—Devices for damping, suppressing, obstructing or conducting sound in acoustic devices
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R3/00—Circuits for transducers, loudspeakers or microphones
    • H04R3/02—Circuits for transducers, loudspeakers or microphones for preventing acoustic reaction, i.e. acoustic oscillatory feedback

Definitions

  • the present invention relates to a singing suppressor which prevents singing from arising owing to acoustic feedback.
  • the methods or devices including amplifiers or amplifier chains built up exclusively of electric and electronic elements are not suited (so also the neutralization or the use of frequency correctors).
  • M. Schroeder Die statinzkurven von grossen Raeumen. Acoustica, Akustician Beihefte 1954, Heft 2, pp. 594 to 600;
  • the value of the increase of the sound pressure level is lower by about 3 to 4 dB.
  • frequency shift is brought about by dual single-sideband modulation or an artifical circuit incorporating a phase-shift circuit.
  • the purpose of the present invention is to provide a device which, beside being of simple construction, effectively suppresses singing owing to acoustic feedback and considerably increases the value of the achievable gain and sound pressure without the risk of harmful distortions.
  • time interval of singing a given time interval is also needed for the generation of singing or self-oscillation. In the following this interval will be referred to as "time interval of singing”.
  • the time interval of singing is in general of the order of milliseconds. If the signal of the frequency and amplitude associated with the singing or self-oscillation appears at the input of the electroacoustic chain and is changed within the time interval of singing, the self-oscillation of the system will fail to come about or will appear only at a much higher amplitude level. If the characteristics of the electroacoustic chain are changed in a way that the chain remains in a condition for singing or self-oscillation for a time shorter than the time interval of self-oscillation, the singing or self-oscillation can be entirely prevented. This can be achieved by inserting a variable delay in the electroacoustic chain.
  • the present invention relates to a singing suppressor device which prevents singing or self-oscillation due to acoustic feedback from arising in an electroacoustic chain incorporating a sound sensing device, an amplifier and a sound transmitter, and which comprises at least one analogue and/or digital delay unit consisting of electrical and electronic elements and having at least one audio frequency input and output, at least one delay period determining control input, and of a delay period dependent on the frequency and/or amplitude of the electrical signal led to the input of the control input.
  • the control input of the delay unit(s) has at least one control generator coupled thereto, directly or at least through a frequency and/or amplitude modulator, for generating an electrical signal varing in time, of the modulator(s) at least one auxiliary generator being coupled to the other input.
  • a control generator for generating a periodical electrical signal of a basic frequency less than 20 Hz, or of a frequency lower than the lower limit of the transmitting band of the electroacoustic chain.
  • a control generator is used that generates a saw-tooth shaped electrical signal, and an electronic interrupter or gain reducing circuit in inserted into the electroacoustic chain in a way that, during the flayback period of the sawtooth signal, this circuit interrupts the path of the audio frequency signal or reduces the gain of the electroacoustic chain.
  • a variant can also be used where a generator is used as the control generator which generates an electrical signal of components of a frequency varying in time, with a random variation, and of less than 20 Hz or less than the frequency of the lower limit of the transmitting band of the electroacoustic chain applied.
  • a signal converter is used for the control or the auxiliary generator, transforming the audio frequency signal transmitted by the electroacoustic chain.
  • the temporal shape, value and frequency of the electrical signal of the control and the auxiliary generator is preferably adjusted by means of a control element.
  • the advantage of the arrangement according to the invention lies in the fact that, by means of relatively simple devices, effective singing suppresion is achieved.
  • the device is so designed to be adjustable by means of control features to different acoustic conditions of halls, spaces, sports establishments, or a TV or radio quiz programme.
  • control features to different acoustic conditions of halls, spaces, sports establishments, or a TV or radio quiz programme.
  • Adjustability is of utmost importance because, according to the results of a study of the statistical characteristics of the sound space, as has already been made clear, the increase of loudness depends on the reverberation time of the hall and on the bandwidth of the electroacoustic chain being used.
  • a singing suppressor device whose characteristics (e.g. the amount and course of the delay time in the temporal order, the frequency, etc.) are variable in a relatively simple manner.
  • characteristics e.g. the amount and course of the delay time in the temporal order, the frequency, etc.
  • maximum increase of the sound pressure can be guaranteed.
  • the singing suppressor device according to the invention has yet other advantageous properties such as the transmission of the originally consonant sound picture in an unchanged (consonant) form, and no non-linear distortions will arise either.
  • the equipment according to the invention is of moderate dimensions and of low weight, it may easily be made portable. Since it contains exclusively electrical and electronic devices or elements, its useful life and operational safety are extremely high.
  • FIG. 1 presents an exemplary embodiment of an amplifying electroacoustic chain in which the inventive singing suppressor device is used
  • FIG. 2 is a schematic block diagram of the device according to the invention.
  • FIG. 3 is a circuit diagram of a delay unit used in one embodiment of the inventive device.
  • FIG. 4 is a block diagram of another embodiment of the singing suppressor device according to the invention.
  • FIG. 1 an electroacoustic chain is shown as it is used for amplification.
  • a hall or space 8 is to be served by loudspeakers or sound radiators 7 with an appropriate sound pressure.
  • an audience 9 is seated wishing to listen to the voice of a speaker or a singer 1, properly amplified or at an appropriate sound pressure level.
  • the voice of the speaker or singer 1 is sensed by a microphone 2 and this microphone transforms it into an electrical signal.
  • the electrical signal of microphone 2 is an audio-frequency signal, amplified by a pre-amplifier 3.
  • a tone control unit or sound corrector 4 has as its function to correct the defects and irregularities of the frequency response (here including the properties of the hall) of the whole transmission chain, and also to satisfy the individual taste of the audience.
  • the inventive singing suppressor device is identified by numeral 5, of which exemplary embodiments are given in FIGS. 2 and 4.
  • the output amplifier stage 6 guarantees a sufficiently high electrical output for the sound radiator(s) 7.
  • electro-acoustic chains have a given transmitting band beyond whose lower and upper frequency limits the chain will not operate at all, or only at a considerably reduced rate. It is also known that at a given gain value this system will, almost without exception, start singing within the transmitting band owing to acoustic feedback, and become useless for normal amplification and listening. The cause of this is that the sound pressure generated by the loudspeaker(s) 7 generates an electrical signal in the microphone 2, which for a given gain then becomes self-supporting.
  • the function of the inventive singing suppressor 5 is to guarantee the adjustability of the gain to a higher value and prevent singing from arising.
  • the hall 8 is the site of a TV or radio quiz programme transmission.
  • the audio-frequency chain also incorporates a high-frequency transmitter and receiver unit, whereas the loudspeaker or sound radiator 7 enables the monitoring of or listening in to the programme.
  • FIG. 2 the block diagram of the singing suppressor according to the invention is shown by way an example.
  • a delay unit 51 is used in the circuit, preferably of an analog arrangement. This unit is presented in detail in FIG. 3.
  • the delay time of the delay unit is defined by the frequency f s of the electrical signal applied to the input of the control unit at U in .
  • the signal of a voltage U s and a frequency f s is generated by an auxiliary generator 52.
  • the voltage U s preferably frequency modulated by means of a frequency modulator 54 with an electrical signal of a voltage U v and a frequency f v provided by a control generator 53.
  • a known bucket brigade device operating on the analogue principle is used as a delay unit.
  • the operation of this device is known and may be followed in FIG. 3: a chain is built up in series of the MOSFET transistors Tr 1 . . . Tr n and the integrated condensers or capacitors C 1 , C 2 . . . C n in a way that the control electrodes of the transistors Tr 1 , Tr 3 , Tr 5 . . . Tr n (i.e. the odd transistors) are led out separately, commoned to a control input t 1 , and so are the even transistors Tr 2 , Tr 4 , Tr 6 . . .
  • Tr n -1 to a terminal t 2 as an input.
  • a square signal is applied, phase shifted with respect to each other by 180°. In this case e.g. the odd transistors will be completely open, the even transistors completely blocked.
  • the signal advancing to the input will be charged during the half-period of the square signal into condenser C 1 through the open transistor Tr 1 . It cannot, however, proceed any further because at the same time transistor Tr 2 will be blocked.
  • transistor Tr 1 will open, the charge in condenser C 1 will be discharged into condenser C 2 . This process follows the whole chain at a time of propagation jointly determined by the number of the transistor-condenser chains used and the basic frequency of the square signal.
  • the auxiliary generator 52 shown in FIG. 2 generates the square signal.
  • the singing suppressor 5 operates also in conjunction with electronic delay of different set-ups or constructions, thus e.g. with an analogue delay unit built up of Varicap diodes and inductances, or a delay unit operating on the digital principle.
  • the controlling signal controls the capacity of the Varicap diodes directly, whereas in the latter case it controls the clock frequency of analogue-digital and digital-analogue transformers and of dynamic stepping registers through a frequency modulator, and produces in this way a delay time that constantly changes in its temporal order.
  • FIG. 4 another possible device 5a according to the invention is shown where a signal converting circuit 55, e.g. a rectifier and a low-pass filter is used as the control generator (instead of 53), whose output signal of a voltage U v and a frequency f v is gained from the audio frequency signal U in to be boosted by way of transformation.
  • a signal converter circuit can e.g. be equipped with a demodulator low-pass filter.

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  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Acoustics & Sound (AREA)
  • Multimedia (AREA)
  • Health & Medical Sciences (AREA)
  • General Health & Medical Sciences (AREA)
  • Otolaryngology (AREA)
  • Signal Processing (AREA)
  • Electrophonic Musical Instruments (AREA)
  • Tone Control, Compression And Expansion, Limiting Amplitude (AREA)
  • Reverberation, Karaoke And Other Acoustics (AREA)
  • Soundproofing, Sound Blocking, And Sound Damping (AREA)
  • Circuit For Audible Band Transducer (AREA)
  • Amplifiers (AREA)
US05/573,989 1974-06-05 1975-05-02 Singing suppressor device Expired - Lifetime US4039753A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
HUEE2241/74 1974-06-05
HUEE2241A HU169185B (da) 1974-06-05 1974-06-05

Publications (1)

Publication Number Publication Date
US4039753A true US4039753A (en) 1977-08-02

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US05/573,989 Expired - Lifetime US4039753A (en) 1974-06-05 1975-05-02 Singing suppressor device

Country Status (14)

Country Link
US (1) US4039753A (da)
AT (1) ATA316575A (da)
BG (1) BG27105A3 (da)
CA (1) CA1027487A (da)
CS (1) CS191931B2 (da)
DD (1) DD118216A5 (da)
DE (1) DE2518840C2 (da)
DK (1) DK246475A (da)
FR (1) FR2274193A1 (da)
GB (1) GB1510691A (da)
HU (1) HU169185B (da)
PL (1) PL95268B1 (da)
SE (1) SE401590B (da)
SU (1) SU673209A3 (da)

Cited By (19)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4449237A (en) * 1982-04-14 1984-05-15 Cincinnati Electronics Corporation Audio feedback suppressor
US4618987A (en) * 1983-12-14 1986-10-21 Deutsche Post, Rundfunk-Und Fernsehtechnisches Zentralamt Large-area acoustic radiation system
US5307417A (en) * 1990-01-16 1994-04-26 Pioneer Electronic Corporation Sound system with howling-prevention function
WO1995028034A2 (en) * 1994-04-12 1995-10-19 Philips Electronics N.V. Signal amplifier system with improved echo cancellation
DE19517469A1 (de) * 1995-05-12 1996-11-14 Sel Alcatel Ag Freisprechverfahren für ein mehrkanaliges Übertragungssystem
US6542611B1 (en) 1998-07-31 2003-04-01 Circuit Research Labs, Inc. Multi-state echo suppressor
US20040153103A1 (en) * 1998-12-30 2004-08-05 Schwartz Herbert E. Soft tissue locking device
SG114546A1 (en) * 2001-05-22 2005-09-28 School Juridical Person Of Fuk Oscillation prevention circuit
US20070165838A1 (en) * 2006-01-13 2007-07-19 Microsoft Corporation Selective glitch detection, clock drift compensation, and anti-clipping in audio echo cancellation
US20070263849A1 (en) * 2006-04-28 2007-11-15 Microsoft Corporation Integration of a microphone array with acoustic echo cancellation and center clipping
US20070263850A1 (en) * 2006-04-28 2007-11-15 Microsoft Corporation Integration of a microphone array with acoustic echo cancellation and residual echo suppression
US20090207763A1 (en) * 2008-02-15 2009-08-20 Microsoft Corporation Voice switching for voice communication on computers
US20090316881A1 (en) * 2008-06-20 2009-12-24 Microsoft Corporation Timestamp quality assessment for assuring acoustic echo canceller operability
US7651509B2 (en) 1999-12-02 2010-01-26 Smith & Nephew, Inc. Methods and devices for tissue repair
US8512375B2 (en) 1999-12-02 2013-08-20 Smith & Nephew, Inc. Closure device and method for tissue repair
US8623051B2 (en) 2005-06-24 2014-01-07 Smith & Nephew, Inc. Tissue repair device
US9314235B2 (en) 2003-02-05 2016-04-19 Smith & Nephew, Inc. Tissue anchor and insertion tool
US9368101B1 (en) * 2012-10-19 2016-06-14 Meyer Sound Laboratories, Incorporated Dynamic acoustic control system and method for hospitality spaces
US20170076738A1 (en) * 2015-02-01 2017-03-16 Board Of Regents, The University Of Texas System Natural ear

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2659028C3 (de) * 1976-12-27 1979-05-31 Dasy Inter S.A., Genf (Schweiz) Schaltungsanordnung zum Verhindern von Rückkopplungen
DE2738339A1 (de) * 1977-08-25 1979-03-01 Bosch Gmbh Robert Hoergeraeteverstaerker
DE3526591A1 (de) * 1985-07-25 1987-01-29 Schmidt Enzmann Dirk Verfahren zur unterdrueckung der rueckkopplung in elektroakustischen anlagen
DE102010044917B4 (de) * 2010-09-09 2015-01-08 Iav Gmbh Ingenieurgesellschaft Auto Und Verkehr Verfahren zur Vermeidung akustischer Rückkopplungen

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3154644A (en) * 1959-11-18 1964-10-27 Philips Corp Artificial acoustic reverberation with feedback and means for preventing sound discontinuittes
US3257510A (en) * 1962-10-15 1966-06-21 Industrial Res Prod Inc Feedback control apparatus
US3429999A (en) * 1966-09-06 1969-02-25 Collins Radio Co Circuit for preventing singing in audio systems
US3749837A (en) * 1972-05-02 1973-07-31 J Doughty Electronic musical tone modifier for musical instruments
US3842204A (en) * 1972-08-16 1974-10-15 D Leslie Pulsato generation system

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1083873B (de) * 1958-10-29 1960-06-23 Telefonbau Verfahren zur Verminderung der Aufschwingfaehigkeit rueckkopplungsfaehiger Systeme fuer Hoerfrequenzen
DE2249257A1 (de) * 1972-10-07 1974-04-11 Itt Ind Gmbh Deutsche Verfahren zum aendern der frequenzen eines nachrichtensignals

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3154644A (en) * 1959-11-18 1964-10-27 Philips Corp Artificial acoustic reverberation with feedback and means for preventing sound discontinuittes
US3257510A (en) * 1962-10-15 1966-06-21 Industrial Res Prod Inc Feedback control apparatus
US3429999A (en) * 1966-09-06 1969-02-25 Collins Radio Co Circuit for preventing singing in audio systems
US3749837A (en) * 1972-05-02 1973-07-31 J Doughty Electronic musical tone modifier for musical instruments
US3842204A (en) * 1972-08-16 1974-10-15 D Leslie Pulsato generation system

Cited By (41)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4449237A (en) * 1982-04-14 1984-05-15 Cincinnati Electronics Corporation Audio feedback suppressor
US4618987A (en) * 1983-12-14 1986-10-21 Deutsche Post, Rundfunk-Und Fernsehtechnisches Zentralamt Large-area acoustic radiation system
US5307417A (en) * 1990-01-16 1994-04-26 Pioneer Electronic Corporation Sound system with howling-prevention function
US5748751A (en) * 1994-04-12 1998-05-05 U.S. Philips Corporation Signal amplifier system with improved echo cancellation
WO1995028034A3 (en) * 1994-04-12 1995-11-30 Philips Electronics Nv Signal amplifier system with improved echo cancellation
WO1995028034A2 (en) * 1994-04-12 1995-10-19 Philips Electronics N.V. Signal amplifier system with improved echo cancellation
DE19517469A1 (de) * 1995-05-12 1996-11-14 Sel Alcatel Ag Freisprechverfahren für ein mehrkanaliges Übertragungssystem
US5901230A (en) * 1995-05-12 1999-05-04 Alcatel N.V. Hands-free communication method for a multichannel transmission system
US6542611B1 (en) 1998-07-31 2003-04-01 Circuit Research Labs, Inc. Multi-state echo suppressor
US20030174847A1 (en) * 1998-07-31 2003-09-18 Circuit Research Labs, Inc. Multi-state echo suppressor
US20080091237A1 (en) * 1998-12-30 2008-04-17 Schwartz Herbert E Suture locking device
US20040153103A1 (en) * 1998-12-30 2004-08-05 Schwartz Herbert E. Soft tissue locking device
US8512374B2 (en) 1998-12-30 2013-08-20 Depuy Mitek, Llc Soft tissue locking device
US8323315B2 (en) 1998-12-30 2012-12-04 Depuy Mitek, Inc. Suture locking device
US9545251B2 (en) 1999-12-02 2017-01-17 Smith & Nephew, Inc. Apparatus for tissue repair
US7887551B2 (en) 1999-12-02 2011-02-15 Smith & Nephew, Inc. Soft tissue attachment and repair
US9492160B2 (en) 1999-12-02 2016-11-15 Smith & Nephew, Inc. Closure device and method for tissue repair
US8512375B2 (en) 1999-12-02 2013-08-20 Smith & Nephew, Inc. Closure device and method for tissue repair
US7651509B2 (en) 1999-12-02 2010-01-26 Smith & Nephew, Inc. Methods and devices for tissue repair
US9295461B2 (en) 1999-12-02 2016-03-29 Smith & Nephew, Inc. Methods for tissue repair
US9833231B2 (en) 1999-12-02 2017-12-05 Smith & Nephew, Inc. Apparatus for tissue repair
US8366744B2 (en) 1999-12-02 2013-02-05 Smith & Nephew, Inc. Apparatus for tissue repair
US9220494B2 (en) 1999-12-02 2015-12-29 Smith & Nephew, Inc. Methods for tissue repair
SG114546A1 (en) * 2001-05-22 2005-09-28 School Juridical Person Of Fuk Oscillation prevention circuit
US9314235B2 (en) 2003-02-05 2016-04-19 Smith & Nephew, Inc. Tissue anchor and insertion tool
US8623051B2 (en) 2005-06-24 2014-01-07 Smith & Nephew, Inc. Tissue repair device
US9173653B2 (en) 2005-06-24 2015-11-03 Smith & Nephew, Inc. Tissue repair device
US20070165838A1 (en) * 2006-01-13 2007-07-19 Microsoft Corporation Selective glitch detection, clock drift compensation, and anti-clipping in audio echo cancellation
US8295475B2 (en) 2006-01-13 2012-10-23 Microsoft Corporation Selective glitch detection, clock drift compensation, and anti-clipping in audio echo cancellation
US7831035B2 (en) 2006-04-28 2010-11-09 Microsoft Corporation Integration of a microphone array with acoustic echo cancellation and center clipping
US7773743B2 (en) 2006-04-28 2010-08-10 Microsoft Corporation Integration of a microphone array with acoustic echo cancellation and residual echo suppression
US20070263850A1 (en) * 2006-04-28 2007-11-15 Microsoft Corporation Integration of a microphone array with acoustic echo cancellation and residual echo suppression
US20070263849A1 (en) * 2006-04-28 2007-11-15 Microsoft Corporation Integration of a microphone array with acoustic echo cancellation and center clipping
US8934945B2 (en) 2008-02-15 2015-01-13 Microsoft Corporation Voice switching for voice communication on computers
US8380253B2 (en) 2008-02-15 2013-02-19 Microsoft Corporation Voice switching for voice communication on computers
US20090207763A1 (en) * 2008-02-15 2009-08-20 Microsoft Corporation Voice switching for voice communication on computers
US8369251B2 (en) 2008-06-20 2013-02-05 Microsoft Corporation Timestamp quality assessment for assuring acoustic echo canceller operability
US20090316881A1 (en) * 2008-06-20 2009-12-24 Microsoft Corporation Timestamp quality assessment for assuring acoustic echo canceller operability
US9368101B1 (en) * 2012-10-19 2016-06-14 Meyer Sound Laboratories, Incorporated Dynamic acoustic control system and method for hospitality spaces
US20170076738A1 (en) * 2015-02-01 2017-03-16 Board Of Regents, The University Of Texas System Natural ear
US11120816B2 (en) * 2015-02-01 2021-09-14 Board Of Regents, The University Of Texas System Natural ear

Also Published As

Publication number Publication date
SE401590B (sv) 1978-05-16
FR2274193B1 (da) 1981-08-07
DK246475A (da) 1975-12-06
HU169185B (da) 1976-10-28
DE2518840C2 (de) 1985-08-22
DE2518840A1 (de) 1976-01-02
PL95268B1 (pl) 1977-10-31
CA1027487A (en) 1978-03-07
DD118216A5 (da) 1976-02-12
ATA316575A (de) 1976-09-15
CS191931B2 (en) 1979-07-31
SU673209A3 (ru) 1979-07-05
GB1510691A (en) 1978-05-10
FR2274193A1 (fr) 1976-01-02
SE7504797L (sv) 1975-12-08
BG27105A3 (bg) 1979-08-15

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